What is the significance of biphasic T waves ?

T waves are the most enigmatic waves in clinical electrocardiography . This is not a surprise , when you consider a tall T wave and a markedly inverted T wave both can be normal in at least in 6 leads out of 12 lead standard electrocardiogram ( V1 V2 V3 , 2 ,3 AVF, ofcourse the AVR )

Common T wave patterns that can either be physiological or pathological

Tall T wave

Inverted T WAVE

Notched or Bifid T wave

Biphasic T wave

* T wave polarity is strongly determined by the direction of QRS vector. Generally it should be on the same direction as QRS. In the presence of conduction defect or chamber hypertrophy this gets altered and is refered toa s secondary repolarisation changes . This has to be differentiated from primary biphasic T waves.

What is a biphasic T wave ?

A T wave which is inscribed on either side of baseline is called biphasic T wave .

Many of the normal persons can have a biphasic Twave.

A typical biphasic wave can be two types

Terminal positivity

Terminal negativity

Terminal negativity is more significant than terminal positivity , especially in CAD.